Somewhere want to document for v4.0.
It looks as if it's long been the case the jitter value forever shrinks
as the continuous (-kla) real time rendering (rtr) option runs. The
user's jitter value needs to be captured aside and restored after each
'frame' in the continuous render.
I checked and frames rendered by the more usual animation mechanisms are
OK with respect to the jitter value.
Bill P.